Waveguide



FIG. 1 is a perspective view of a waveguide showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof; and,

FIG. 4 is a side plan view thereof.

The broken lines depict portions of the waveguide that form no part of the claimed design. 

CLAIM The ornamental design for a waveguide, as shown and described. 